The present invention relates to a system for locking fan cowls of an aircraft nacelle, to an aircraft nacelle comprising such a locking system, and to an aircraft comprising such a nacelle.
An aircraft comprises at least one nacelle which houses an engine, for example of the jet engine type, and which is suspended from a pylon. The nacelle generally comprises two fan cowls which may be opened so as to be able to carry out maintenance on the engine.
Each fan cowl is articulated about an opening axis parallel to the longitudinal axis of the nacelle and arranged in the upper part of the fan cowls, and the two fan cowls are arranged symmetrically on either side of the pylon.
Each fan cowl can thus move between a closed position, in which the fan cowl is arranged in the extension of the outer surface of the nacelle so as to cover the casing of the fan, and an open position, in which an operator has access to the engine.
The lower edges of the fan cowls, which are located in the lower part of the nacelle, are substantially contiguous in the closed position and are held in this locked position by multiple locking systems which are distributed along the contiguous lower edges of the fan cowls.
FIG. 1 shows a section through a locking system 50 of the prior art, between a first fan cowl 10 and a second fan cowl 20. The first fan cowl 10 bears a latching point 52, also called a “keeper”, which is attached at the lower edge of the first fan cowl 10. The locking system 50 also comprises a hook 54 and a handle 58 which are mounted such that they can rotate with respect to one another about a rotation spindle 56.
The handle 58 and the hook 54 are mounted together and able to rotate, at the lower edge of the second fan cowl 20 via the intermediary of an articulation 62, about the rotation spindle 56. The articulation 62 consists of two articulated rods which are mounted so as to be able to rotate with respect to one another, and of which one is mounted so as to be able to rotate on the second fan cowl 20, the other bearing the handle 58/hook 54 assembly.
In the engaged position, the hook 54 receives the latching point 52 and the locking system 50 is locked when the handle is folded down between the fan cowls 10 and 20.
Before takeoff, an operator must check that the locking system 50 is properly engaged and locked. The fan cowls 10 and 20 tend to move toward one another under their own weight, and an operator may incorrectly assume, after a visual check, that the locking system is engaged and locked.